A thin-film transistor (TFT) consists of a channel region located between source and drain (S/D) regions. The resistance of the channel is modulated by the voltage on the gate electrode, while that of the S/D regions is not. For a conventional metal-oxide (MO) TFT, Schottky barriers are formed at the junctions where the S/D conductors contact the metal oxide layer (e.g., indicated by lines 101 of FIG. 1). The resistance associated with such a junction is high, resulting in lowering of the on-state current. Accordingly mechanisms to reduce the resistance of the S/D regions are desired. In some aspects, high resistance associated with the Schottky barrier can be reduced if the conductivity of the MO region under the S/D conductor coverage is increased. Existing techniques for increasing the conductivity of the S/D regions incorporate extrinsic dopants in the MO of the S/D by plasma treatment or ion implantation. These existing techniques are associated with various drawbacks. For example, hydrogen can be doped into the MO using the plasma treatment but it is thermally unstable. Other relatively stable extrinsic dopants, such as boron and phosphorus, require a relatively expensive ion implantation process and an additional activation annealing.
The above-described deficiencies of conventional MOTFT devices are merely intended to provide an overview of some of problems of current technology, and are not intended to be exhaustive. Other problems with the state of the art, and corresponding benefits of some of the various non-limiting embodiments described herein, may become further apparent upon review of the following detailed description.